The present invention relates to a data transmission method usable, for example, in a facsimile machine that stores received documents in a mailbox before printing the documents.
A mailbox is a password-protected memory area in a facsimile machine, storing received facsimile image data addressed to a specific user. The mailbox function is implemented by use of the SUB (subaddress) signal defined in Recommendation T.30 of the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T), entitled xe2x80x9cProcedures for Document Facsimile Transmission in the General Switched Telephone Network.xe2x80x9d Before sending a facsimile document, referred to in Recommendation T.30 as a message, the transmitting facsimile machine sends the SUB signal, followed by a subaddress designating a mailbox in the receiving facsimile machine. The receiving facsimile machine stores all pages of the received message in the designated mailbox, and does not print the message until the user of the mailbox gives a printing command.
Because of the limited size of the mailbox memory area, if the user does not check the mailbox often enough, the memory area may become full during the reception of a facsimile transmission, at which point the facsimile transmission is forced to end without being completed. Further facsimile transmissions to the mailbox are then disabled, until the user makes more space available by printing at least some of the stored messages.
A problem that arises in this situation is how to retransmit the facsimile message that was interrupted when the mailbox became full. A simple procedure is to retransmit the entire message, but this procedure is often wasteful, because the initial part of the message may already have been received and stored. If only the pages that could not be received are retransmitted, however, the user at the receiving facsimile machine may have difficulty matching these remaining pages with the part of the facsimile transmission that was received earlier. What the user of the transmitting facsimile machine would like to do is to send only the pages that could not be sent before, and have the receiving facsimile machine add them to the stored pages of the message.
Other problems associated with mailboxes include mistaken transmission of a message to the wrong mailbox, and problems that occur in facsimile transmission in general, such as transmission of unnecessary pages or omission of necessary pages.
It is accordingly an object of the present invention to enable pages to be added to a message that has already been transmitted, as part of the same message.
A more general object is to enable a message that is transmitted from a first communication machine to a second communication machine and is stored in a memory area in the second communication machine to be altered after being transmitted.
In the invented data transmission method, a first communication machine originates a first call to a second communication machine and transmits image data to the second communication machine. The image data are stored in a memory in the second communication machine, without being output immediately.
After the first call has been terminated, the first communication machine originates a second call to the second communication machine, and sends a command instructing the second communication machine to alter the image data transmitted in the first call. The image data stored in the memory are altered as instructed. Later, the altered image data are output at the second communication machine.
The alteration may comprise adding a new page to the pages already transmitted, inserting a new page, replacing a page, deleting a page, or overlaying new image data on a page. Some alterations, such as page deletion, can be made by altering control information associated with the stored image data, and all alterations may involve such alteration of control information. The alteration instructions may be sent to the second communication machine as part of a subaddress, specifying a mailbox in which the image data are stored in the second communication machine. dr
In the attached drawings:
FIG. 1 illustrates the addition of a new page to a stored facsimile message;
FIG. 2 is a block diagram of a facsimile machine;
FIG. 3 is a flowchart illustrating the transmission of a facsimile document to a mailbox;
FIG. 4 is a protocol sequence diagram of a facsimile transmission addressed to a mailbox;
FIG. 5 is a protocol sequence diagram illustrating the addition of the new page;
FIG. 6 illustrates the structure of the message control table in FIG. 2;
FIG. 7 is a flowchart illustrating a subaddress check performed in the receiving facsimile machine;
FIG. 8 is a flowchart illustrating the reception of a two-page facsimile message;
FIG. 9 is a flowchart illustrating the reception of an additional page;
FIG. 10 illustrates the insertion of a new page into a stored facsimile message;
FIG. 11 is a protocol sequence diagram illustrating the insertion of the new page;
FIG. 12 is a flowchart illustrating the reception of the inserted page;
FIG. 13 illustrates the replacement of a page in a stored facsimile message;
FIG. 14 is a protocol sequence diagram illustrating the transmission of a replacement page;
FIG. 15 is a flowchart illustrating the reception of the replacement page;
FIG. 16 illustrates the deletion of a page from a stored facsimile message;
FIG. 17 is a protocol sequence diagram illustrating the transmission of the deletion command;
FIG. 18 is a flowchart illustrating the reception of the deletion command;
FIG. 19 illustrates the modification of an existing page in a stored facsimile message;
FIG. 20 shows an example of the existing page;
FIG. 21 shows the modified page;
FIG. 22 shows an overlay page that is combined with the existing page;
FIG. 23 is a protocol sequence diagram illustrating the transmission of the overlay page; and
FIG. 24 is a flowchart illustrating the reception of the overlay page.